Knob and related sensing circuit

The present invention relates to a knob sensing technique, and more particularly, to a sensing technique for a knob on a touch panel.

Touch functions gradually become popular in vehicles'center information display (CID) systems. When environmental settings of a car (such as the temperature of air conditioning and the volume of car audio) need to be adjusted, the driver must focus more on the touch position and relevant settings displayed on the screen, thus affecting driving safety.

In order to improve driving safety, a knob on a touch panel may be applied in the CID system, where a physical knob is disposed on the touch screen. Therefore, the driver can easily adjust the settings by controlling the knob without being distracted by the displayed values.

It is therefore an objective of the present invention to provide a knob on a touch panel and a related sensing circuit.

An embodiment of the present invention discloses a knob, which is disposed on a touch panel. The touch panel comprises a first touch sensor, a second touch sensor and a third touch sensor. The knob comprises a bottom surface and a first connector. The bottom surface comprises a sensing electrode, which is aligned with the first touch sensor; a first common electrode, which is aligned with the second touch sensor and receives a first reference voltage from the second touch sensor; and a second common electrode, which is aligned with the third touch sensor and receives a second reference voltage from the third touch sensor. The first connector controls the sensing electrode to be conducted with the first common electrode and the second common electrode or not when the knob rotates. A touch sensing circuit of the touch panel determines a rotation direction of the knob according to a signal variation of the first touch sensor.

Another embodiment of the present invention discloses a sensing circuit, which is coupled to a knob. The sensing circuit comprises a receiving circuit and a processing circuit. The receiving circuit receives a signal variation from the knob. The processing circuit, coupled to the receiving circuit, determines a rotation direction of the knob according to the signal variation. The signal variation is received through a first touch sensor aligned with and coupled to a sensing electrode of the knob, and the signal variation is generated according to whether the sensing electrode is conducted with a first common electrode and a second common electrode in the knob.

These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.

1 FIG. 1 FIG. 10 10 10 10 10 10 10 10 10 10 10 is a schematic diagram of the bottom of a knob. As shown in, the knobmay be attached on a touch panel. The bottom of the knobincludes an electrode RA. The position of the electrode RA may change by turning the knob. When a user contacts the knob, the voltage of the electrode RA may become the ground level through the knoband the user. When the sensing circuit of the touch panel senses that the user is turning the knobthrough the touch electrodes on the touch panel, the sensing circuit may determine the rotation direction and angle θ of the knobbased on the sensed position of the electrode RA. More specifically, when the user touches the knob, the voltage level of the electrode RA changes, and a sensing signal is also sensed by the touch panel. At this time, the information of the sensing signal related to the position of the electrode RA may be sent to a back-end sensing circuit (e.g., the touch sensor chip for controlling the touch panel), which may determine the state of the knobaccording to the distribution of the appeared sensing signals. For example, the sensing circuit may utilize an appropriate algorithm to analyze the sensing signals to determine the position of the electrode RA, so as to determine the rotation direction and angle θ of the knob.

2 FIG. 2 FIG. 20 20 20 is a schematic diagram of another knob. As shown in, the knobincludes sensing electrodes RA and RB and a common electrode COM. Based on the state of the knob, the sensing electrode RA may selectively be connected to (on) or disconnected from (off) the common electrode COM, and the sensing electrode RB may be selectively connected to or disconnected from the common electrode COM.

20 20 The knobis attached on a touch panel. The touch panel has multiple touch sensing electrodes, where a touch sensor chip or touch with display driver integration (TDDI) circuit may apply a ground signal to a first touch sensing electrode corresponding to the common electrode COM. At this time, the common electrode COM may also sense the ground signal to make the voltage of the common electrode COM become the ground level. When the sensing electrode RA or RB is electrically connected to the common electrode COM, the voltage of the sensing electrode RA or RB may also become the ground level. At this time, a second touch sensing electrode corresponding to the sensing electrode RA or a third touch sensing electrode corresponding to the sensing electrode RB on the touch panel may also sense the ground level of the sensing electrode RA or RB; hence, the touch sensor chip or the TDDI circuit may detect the signals through the second touch sensing electrode or the third touch sensing electrode to determine the operations of the knob. It should be noted that the sensing electrode RA or RB or the common electrode COM may correspond to multiple second touch sensing electrodes, multiple third touch sensing electrodes or multiple first touch sensing electrodes.

20 20 20 20 20 20 20 20 20 20 2 FIG. 2 FIG. 2 FIG. 2 FIG. In another embodiment, the sensing electrodes RA and RB may be connected to or disconnected from the common electrode COM during the rotation of the knobthrough structural design, such as the shape or structure of the electrodes. Therefore, when the knobis rotated, the connections between the sensing electrodes RA and RB and the common electrode COM may be modified. The back-end sensing circuit may thereby determine the state of the knobaccording to the sensed signals. For example, in the upper left part of, the sensing electrodes RA and RB are both connected to the common electrode COM, and this is the first state of the knob. After the rotations of the knob, the electrical connection between the sensing electrode RA and the common electrode COM is disconnected, while the sensing electrode RB and the common electrode COM are still electrically connected, as shown in the upper right part of, and this is the second state of the knob. After the knobfurther rotates, the electrical connection between the sensing electrode RB and the common electrode COM is disconnected, while the sensing electrode RA and the common electrode COM are electrically connected, as shown in the lower left part of, and this is the third state of the knob. After the knobfurther rotates, the electrical connections between the sensing electrodes RA and RB and the common electrode COM are both disconnected, as shown in the lower right part of, and this is the fourth state of the knob. The above four states may be detected by the touch sensor chip or the TDDI circuit of the touch panel.

20 20 In such a situation, the touch sensor chip may determine whether the knobis rotating clockwise or counterclockwise according to continuous state changes of the knob(i.e., the changes of electrical connections between these electrodes).

3 FIG. 30 30 1 2 30 1 2 is a schematic diagram of a knobaccording to an embodiment of the present invention, where the plane diagrams at several positions are shown. The knobincludes a sensing electrode RX and two common electrodes COMand COM. According to the rotation of the knob, the common electrodes COMand COMmay be controlled to be electrically connected to the sensing electrode RX or not under different states, to generate different sensing signal amounts.

3 FIG. 30 300 300 300 300 300 30 As the plane diagram of the bottom layer shown in the left side of, the knobmay be deployed on a touch panel, where each grid refers to a touch sensor on the touch panel. This touch sensor may represent a touch sensing electrode, which is the minimum unit for performing touch sensing on the touch panel. In an embodiment, the touch sensing electrode may serve as a common electrode during a display period of the touch panel, and serve as a touch sensing electrode during a touch period. In another embodiment, the touch panelis an organic light emitting diode (OLED) touch panel, and thus the touch sensing electrode may not be operated as a common electrode during the display period as in the liquid crystal display (LCD) panel. The touch sensor chip of the touch panel or the sensing circuit included in the touch sensor chip may determine whether there is a touch or whether the sensing electrode RX of the knobis sensed according to the capacitance variations on the touch sensor.

3 FIG. 1 2 1 2 As shown in, the sensing electrode RX and the common electrodes COMand COMmay be respectively fixed on multiple touch sensors and aligned with these touch sensors. In another embodiment, the sensing electrode RX and/or the common electrodes COMand COMmay be located on only one touch sensor, and thus within the sensing range of only one touch sensor.

1 2 1 2 1 1 2 2 3 2 3 2 3 1 3 FIG. In an embodiment, the sensing circuit may apply a specific voltage to the touch sensors under the common electrodes COMand COM, where the specific voltage may be a ground voltage. In another embodiment, the sensing circuit may apply different reference voltages to the touch sensors under the common electrodes COMand COM. For example, as shown in, the touch sensor under the sensing electrode RX is a first touch sensor S, the touch sensor under the common electrode COMis a second touch sensor S, and the touch sensor under the common electrode COMis a third touch sensor S. The sensing circuit may apply the ground voltage to the second touch sensor Sand apply a negative voltage to the third touch sensor S. By applying different voltages to the second touch sensor Sor the third touch sensor S, the sensing circuit will let the capacitance variations (or referred to as signal amounts or signal variations) sensed by the first touch sensor Sto have more evident differences.

1 2 1 1 1 2 When the knob is rotating, the sensing electrode RX may be respectively electrically connected, or simultaneously electrically connected, or not electrically connected to the common electrodes COMand COM. The sensing circuit applies a driving signal to the first touch sensor Sunder the sensing electrode RX and receives a sensing signal from the first touch sensor S. The sensing circuit may determine the connecting state of the sensing electrode RX and the common electrodes COMand COMat this time according to the signal amount of the sensed signal, and determine the knob operations according to the signal amount of the continuously read signals.

30 1 2 30 30 1 2 1 2 1 2 30 1 2 30 1 2 3 FIG. In various embodiments of the present invention, through the structural design inside the knob, the state of whether the common electrode COMor COMis electrically connected to the sensing electrode RX may change during rotation of the knob, so that the sensing circuit may determine the rotation direction and angle of the knobaccording to the sensed signal amount of the sensing electrode RX. As the plane diagram of the rotation layer shown in the middle of, the sensing electrode RX and the common electrodes COMand COMare respectively coupled to a corresponding electrode ring, where the electrode ring of the common electrode COMis located inside the electrode ring of the sensing electrode RX, and the electrode ring of the common electrode COMis located outside the electrode ring of the sensing electrode RX. The electrode rings of the common electrodes COMand COMare provided with a sawtooth structure. When the knobrotates, the electrode rings of the common electrodes COMand COMwill rotate accordingly, so that the protruding part of the sawtooth shape contacts the electrode ring of the sensing electrode RX when the knobrotates to several angles, thereby making the common electrode COMor COMand the sensing electrode RX electrically connected to each other.

4 FIG. 4 FIG. 3 FIG. 1 2 402 404 406 408 402 1 412 414 2 422 424 404 300 300 402 402 404 414 1 300 1 300 412 1 412 414 424 2 300 2 300 422 2 422 424 402 404 406 408 412 414 1 1 422 424 2 2 illustrates the detailed structure of the electrode rings of the sensing electrode RX and the common electrodes COMand COMin a disassembled manner. The sensing electrode RX is coupled to a sensing electrode ring, and an electrode postand connecting postsandare deployed on the sensing electrode ring. The common electrode COMis coupled to a common electrode ringand an electrode post. The common electrode COMis also coupled to a common electrode ringand an electrode post. Referring toalong with, the electrode postis disposed above the sensing electrode RX on the touch paneland connected between the sensing electrode RX on the touch paneland the sensing electrode ring, so that the sensing electrode RX and the sensing electrode ringare electrically connected to each other through the electrode post. Similarly, the electrode postis disposed above the common electrode COMon the touch paneland connected between the common electrode COMon the touch paneland the common electrode ring, so that the common electrode COMand the common electrode ringare electrically connected to each other through the electrode post. The electrode postis disposed above the common electrode COMon the touch paneland connected between the common electrode COMon the touch paneland the common electrode ring, so that the common electrode COMand the common electrode ringare electrically connected to each other through the electrode post. Note that in the present invention, the sensing electrode ring, the electrode postand the connecting postsandmay be regarded as conductive elements coupled to the sensing electrode RX, or may be regarded as parts of the sensing electrode RX. Similarly, the common electrode ringand the electrode postmay be regarded as conductive elements coupled to the common electrode COM, or may be regarded as parts of the common electrode COM. The common electrode ringand the electrode postmay be regarded as conductive elements coupled to the common electrode COM, or may be regarded as parts of the common electrode COM.

406 402 1 406 402 412 1 30 406 412 412 402 1 30 406 412 406 412 412 402 1 In addition, the connecting postmay be a conductor protruding from the sensing electrode ringtoward the common electrode COM, and the connecting postand the sensing electrode ringare electrically connected to each other. Correspondingly, the common electrode ringof the common electrode COMhas a sawtooth structure. When the knobrotates to several angles, the connecting postmay contact the sawtooth protruding part on the common electrode ring, so that the common electrode ringis electrically connected to the sensing electrode ring, and therefore the common electrode COMis electrically connected to the sensing electrode RX. When the knobrotates to other angles, the position of the connecting postis aligned with the sawtooth recessing part on the common electrode ring, and thus the connecting postdoes not contact the common electrode ring, so that the common electrode ringis not electrically connected to the sensing electrode ring, and thus there is no electrical connection between the common electrode COMand the sensing electrode RX.

408 402 2 408 402 422 2 30 408 422 422 402 2 30 408 422 408 422 422 402 2 Similarly, the connecting postmay be a conductor protruding from the sensing electrode ringtoward the common electrode COM, and the connecting postand the sensing electrode ringare electrically connected to each other. Correspondingly, the common electrode ringof the common electrode COMhas a sawtooth structure. When the knobrotates to several angles, the connecting postmay contact the sawtooth protruding part on the common electrode ring, so that the common electrode ringis electrically connected to the sensing electrode ring, and therefore the common electrode COMis electrically connected to the sensing electrode RX. When the knobrotates to other angles, the position of the connecting postis aligned with the sawtooth recessing part on the common electrode ring, and thus the connecting postdoes not contact the common electrode ring, so that the common electrode ringis not electrically connected to the sensing electrode ring, and thus there is no electrical connection between the common electrode COMand the sensing electrode RX.

30 402 412 422 30 406 408 402 412 422 406 408 412 422 406 408 1 2 30 In an embodiment, when the knobrotates, the sensing electrode ringis fixed, and the common electrode ringsandrotate with the knob. In such a situation, the positions of the connecting postsandon the sensing electrode ringare fixed. With the rotation of the common electrode ringsand, the protruding part and the recessing part of a sawtooth sequentially overlap the positions of the connecting postsand, so as to change the contact state between the common electrode ringsandand the corresponding connecting postsand, thereby changing the electrical connection state between the common electrodes COMand COMand the sensing electrode RX. In such a situation, the signal amount of the touch sensor under the sensing electrode RX may change. The back-end sensing circuit (such as the sensing circuit in the touch sensor chip of the touch panel) may thereby determine the rotation direction and angle of the knobaccordingly.

30 412 422 402 30 406 408 402 30 412 422 412 422 406 408 30 In another embodiment, when the knobrotates, the common electrode ringsandare fixed; instead, the sensing electrode ringrotates with the knob. In such a situation, the positions of the connecting postsandon the sensing electrode ringcontinuously change during the rotation of the knob, while the position of the sawtooth on the common electrode ringsandkeeps unchanged. This may also change the contact state between the common electrode ringsandand the corresponding connecting postsand, so as to realize the determination of the knobrotation.

5 FIG. 30 406 408 30 412 422 406 408 412 422 406 408 406 408 412 422 402 412 422 406 408 In order to illustrate the structure of the knob of the present invention more clearly,further illustrates a side view of the electrode ring arrangement in the knob, where the cross-sections of positions A and B are shown. Position A is a position where the connecting postsandare located. In this embodiment, the state of the knobis that the sawtooth protruding parts of the common electrode ringsandboth rotate to the positions of the connecting postsand; hence, the common electrode ringsandare in contact with the connecting postsandrespectively, causing the conducted/electrically connected state. Position B is a position without the connecting postsand, where the common electrode ringsandare in the sawtooth recessing part, which is shorter and would not overlap the sensing electrode ring; hence, the common electrode ringsanddo not contact the connecting postsand.

6 FIG. 402 404 1 412 1 414 shows the cross-sections of other positions C and D. Position C is a position of the sensing electrode RX on the panel. As can be seen from the corresponding side view, the sensing electrode ringis electrically connected to the sensing electrode RX through the electrode post. Position D is a position of the common electrode COMon the panel. As can be seen from the corresponding side view, the common electrode ringis electrically connected to the common electrode COMthrough the electrode post.

30 As can be seen, the knobof the present invention includes only one sensing electrode RX. As for the back-end sensing circuit, the sensing signal used to determine the knob operation only needs to be received through one sensing electrode RX. More specifically, the sensing circuit only needs to receive the sensing signal from the touch sensor under the sensing electrode RX, where the signals from other positions need not to be considered. In addition, the sensing circuit does not need to receive sensing signals corresponding to multiple sensing electrodes to perform more complex comparison and determination. In such a situation, the sensing circuit only requires one receiving channel. This may simplify the structure and operation of the receiving end of the sensing circuit, thereby reducing the costs.

30 3 6 FIGS.- Note that the structure of the knobshown inas illustrated above is one of various implementations of the present invention. In other embodiments, different numbers of common electrodes may be used to achieve more flexible determination of signal amount variations. In an embodiment, an additional common electrode may be included to realize the press detection of the knob.

7 FIG. 3 FIG. 7 FIG. 7 FIG. 70 70 30 70 30 70 3 3 3 1 2 70 70 700 3 700 4 4 3 1 is a schematic diagram of another knobaccording to an embodiment of the present invention. The structure of the knobis similar to the structure of the knobshown in, so elements having similar functions are denoted by the same symbol. As shown in, the difference between the knoband the knobis that the knobfurther includes a common electrode COM. This common electrode COMis configured to realize the pressing function. More specifically, according to whether the common electrode COM(and other common electrodes COMand COM) is electrically connected to the sensing electrode RX, the back-end sensing circuit may determine whether the knobis pressed. Similarly, the knobis disposed on a touch panel, and the common electrode COMmay be disposed above one or more touch sensors of the touch panel(i.e., the fourth touch sensor Sshown in). Therefore, by applying the same or different reference voltages to the fourth touch sensor S, whether the common electrode COMand the sensing electrode RX are electrically connected may be determined based on the signal amount sensed by the first touch sensor S.

8 FIG. 4 FIG. 8 FIG. 7 FIG. 1 2 3 1 2 3 802 804 806 804 3 300 3 300 802 3 802 804 802 804 806 3 3 illustrates the detailed structure of the electrode rings of the sensing electrode RX and the common electrodes COM, COMand COMin a disassembled manner. The electrode rings and electrode posts of the sensing electrode RX and the common electrodes COMand COMare deployed in the same manner as in, and will not be narrated herein. The common electrode COMis coupled to a common electrode ring, an electrode postand a connector. Referring toalong with, the electrode postis disposed above the common electrode COMon the touch paneland connected between the common electrode COMon the touch paneland the common electrode ring, so that the common electrode COMand the common electrode ringare electrically connected to each other through the electrode post. Note that in the present embodiment, the common electrode ring, the electrode postand the connectormay be regarded as conductive elements coupled to the common electrode COM, or may be regarded as parts of the common electrode COM.

802 806 802 802 412 70 806 402 412 422 3 1 2 In addition, the common electrode ringis located at the outermost side of all electrode rings. The connector, which may be a conductor extending inwardly from the common electrode ring, is electrically connected to the common electrode ring, and may extend to overlap the innermost common electrode ring. Therefore, when the knobis pressed, the connectormay contact the sensing electrode ringand the common electrode ringsand, so that the common electrode COMis electrically connected to the sensing electrode RX and the common electrodes COMand COM.

802 3 70 70 70 3 It should be noted that the common electrode ringof the common electrode COMmay be designed to be stationary when the knobrotates, or may be designed to rotate with the knobaccording to system requirements. As long as the pressing operation of the knobmay change the electrical connection relationship between the common electrode COMand the sensing electrode RX, thereby changing the signal amount generated by the sensing electrode RX, the related implementations should fall within the scope of the present invention.

70 3 70 406 408 806 802 806 422 402 412 806 1 806 2 806 3 806 1 806 2 806 3 806 806 9 FIG. In order to illustrate the structure of the knoband the operation of the common electrode COMmore clearly,further illustrates a side view of the electrode ring arrangement in the knob, where the cross-sections of positions A and B are shown. In addition to having the connecting postsand, position A is also a position where the connectorof the common electrode ringis located. It can be seen from the side view corresponding to position A that the connectorextends above the electrode rings,and, and vertical connecting posts_,_and_are disposed above each electrode ring. The connecting posts_,_and_may be regarded as conductive elements coupled to the connector, or may be regarded as parts of the connector.

9 FIG. 70 900 802 422 70 900 802 806 1 806 2 806 3 422 402 412 3 1 2 70 802 806 1 806 2 806 3 422 402 412 3 1 2 1 3 70 As shown in, the knobincludes a pressing clip, which is disposed between the common electrode ringsand. When the knobis not pressed, the pressing clipmay push the common electrode ringto a higher position, so that there are small gaps between the connecting posts_,_and_and the electrode rings,and, respectively, and they are not conducted with each other. At this time, the common electrode COMis not electrically connected to the sensing electrode RX and other common electrodes COMand COM. When the knobis pressed, the common electrode ringand the connecting posts_,_and_move downwards to contact the corresponding electrode rings,and, respectively, so that the common electrode COMis electrically connected to all of the sensing electrode RX and other common electrodes COMand COM. In such a situation, the sensing electrode RX may receive signals from the common electrodes COM-COM, so the back-end sensing circuit may determine that the knobis pressed accordingly.

9 FIG. 10 FIG. 6 FIG. 3 802 3 804 70 1 also illustrates the cross-section of position B. Position B is a position of the common electrode COMon the panel. As can be seen from the corresponding side view, the common electrode ringis electrically connected to the common electrode COMthrough the electrode post.further illustrates the cross-sections of other positions C and D in the knob, which correspond to the positions of the sensing electrode RX and the common electrode COMon the panel, respectively. Their detailed structures are similar to those shown in, and will not be narrated herein.

70 1 3 70 70 Based on the structure of the knobas described above, the sensing electrode RX may be electrically connected to different numbers of common electrodes COM-COMunder different rotational states or pressing states, so as to generate different levels of signal amounts in the touch sensor under the sensing electrode RX. Therefore, the sensing circuit may determine the state of the knobby detecting the signal amount of the touch sensor(s), so as to determine the rotation direction and angle of the knoband also realize the determination of press.

70 70 70 1100 70 70 1100 70 1100 70 70 11 11 FIGS.A-D In an embodiment, the knobis configured to have 4 different states.illustrate the sensing system in which the knobis in these 4 different states, respectively. The sensing system includes the knoband a sensing circuitused to detect the knob. In an embodiment, the knobmay be disposed on a touch panel, and the sensing circuitmay be used for controlling/driving the touch panel and detecting the operation of the knob. In an embodiment, the sensing circuitmay be an integrated circuit (IC) disposed in a chip. It may be connected to the touch sensors on the touch panel corresponding to the electrodes of the knobthrough one or more pins of the chip, for performing detection of the knob.

1100 1102 1104 1102 70 1102 1 1102 1104 1102 70 1104 70 In detail, the sensing circuitincludes a receiving circuitand a processing circuit. The receiving circuitis used for receiving a sensing signal VRX from the knob. More specifically, the sensing signal VRX received by the receiving circuitcomes from the touch sensor(s) corresponding to the sensing electrode RX, such as the one or more touch sensors under the sensing electrode RX (i.e., the first touch sensor Sin the above embodiment). In an embodiment, the receiving circuitmay output a driving signal to the touch sensor(s) under the sensing electrode RX, to correspondingly receive the sensing signal VRX from the touch sensor(s). The processing circuit, which is coupled to the receiving circuit, may determine the state of the knobaccording to the signal amount of the sensing signal VRX. For example, the processing circuitcontains an algorithm, which may be used to determine which state the knobis in (such as which angle it rotates to or whether it is pressed) based on the signal distribution of the touch sensor under the sensing electrode RX.

1100 1 3 1 3 70 1 3 1 3 70 1100 In addition, the sensing circuitmay also include a driving circuit (not illustrated), which may apply a reference voltage (e.g., a ground voltage) to the touch sensors corresponding to the common electrodes COM-COM(such as the touch sensors under the common electrodes COM-COM) when detecting the knob. This reference voltage may be coupled to the common electrodes COM-COM. Depending on whether each of the common electrodes COM-COMis electrically connected to the sensing electrode RX, signals with different magnitudes may be generated on the sensing electrode RX. These signals are then coupled to the touch sensor under the sensing electrode RX through the parasitic capacitance between the knoband the panel, thereby generating the sensing signal VRX that may be detected by the sensing circuit.

7 9 FIGS.and 11 11 FIGS.A-D 9 FIG. 70 1 2 70 1 2 3 70 1 3 Referring toalong with, in the structural design of the knob, the common electrodes COMand COMare used to perform rotation detection. When the knobrotates to different angles, there may be different numbers of common electrodes COMand COMelectrically connected to the sensing electrode RX, so as to generate different signal amounts on the touch sensor under the sensing electrode RX, where the signal amounts correspond to different magnitudes of the sensing signal VRX. The common electrode COMis used to perform pressing detection. As shown in, when the knobis pressed, the common electrodes COM-COMare all electrically connected to the sensing electrode RX, thereby generating a larger signal amount on the touch sensor under the sensing electrode RX.

70 70 1 2 70 3 11 FIG.A As mentioned above, the knobis configured to have 4 different states, which are denoted by 0C, 1C, 2C and 3C, respectively.illustrates the state 0C. The state 0C means that when the knobrotates to a specific angle, neither the common electrode COMnor the common electrode COMis electrically connected to the sensing electrode RX. At this time, the knobis not pressed, so the common electrode COMis not electrically connected to the sensing electrode RX either. In such a situation, the sensing electrode RX does not have any signal from the common electrode, and therefore the touch sensor under the sensing electrode RX does not have any signal.

11 FIG.B 70 1 2 70 3 illustrates the state 1C. The state 1C means that when the knobrotates to a specific angle, the common electrode COMis electrically connected to the sensing electrode RX while the common electrode COMis not electrically connected to the sensing electrode RX. At this time, the knobis not pressed, so the common electrode COMis not electrically connected to the sensing electrode RX. In such a situation, the sensing electrode RX is electrically connected to only 1 common electrode, and the generated signal is weaker.

11 FIG.C 70 1 2 70 3 illustrates the state 2C. The state 2C means that when the knobrotates to a specific angle, the common electrodes COMand COMare both electrically connected to the sensing electrode RX. At this time, the knobis not pressed, so the common electrode COMis not electrically connected to the sensing electrode RX. In such a situation, the sensing electrode RX is electrically connected to 2 common electrodes, and the generated signal is larger (compared with the state 1C).

11 FIG.D 70 1 3 illustrates the state 3C. The state 3C means that when the knobis pressed, the common electrodes COM-COMare all electrically connected to the sensing electrode RX. In such a situation, the sensing electrode RX is electrically connected to 3 common electrodes, and the generated signal is the maximum.

1104 1100 70 70 70 70 As a result, by detecting the signal amount, the processing circuitin the sensing circuitmay determine which state the knobis in, and thereby determine the rotation direction and angle of the knoband determine whether the knobis pressed, to realize various operations of the knobaccordingly.

1100 70 1 3 1100 1100 As mentioned above, the sensing circuitreceives the sensing signal VRX from the touch sensor corresponding to the sensing electrode RX, and determines the state of the knobthrough the signal amount of the sensing signal VRX. Since the detected touch sensor is under the sensing electrode RX and is close to the sensing electrode RX but not electrically connected, the signal on the sensing electrode RX would generate capacitance variations on the touch sensor through capacitance coupling. In addition, the signal on the sensing electrode RX comes from the common electrodes COM-COMthat are electrically connected to the sensing electrode RX and applied with a ground voltage. When the number of electrically connected common electrodes is larger, the equivalent capacitance variation produced on the touch sensor under the sensing electrode RX is also larger. When the knob detection is performed, the driving signal output by the sensing circuitwill charge or discharge the capacitors on the touch sensor(s). The current generated during the charging or discharging process is thereby received by the sensing circuitas the sensing signal VRX.

1102 1100 1100 1104 1102 In an embodiment, the receiving circuitin the sensing circuitincludes an analog front-end (AFE) circuit, which may be coupled to the touch sensor through a sensing terminal of the chip of the sensing circuit. The current generated by this touch sensor will flow through the sensing terminal to be received by the AFE circuit. For example, the AFE circuit may include a resistor, which is used to convert the current from the touch sensor into the sensing signal VRX in the voltage form, then the back-end analog-to-digital converter (ADC) converts it to the digital form, and then the signal is sent to the processing circuitto perform determination. Corresponding to different capacitance variations on the touch sensor, the AFE circuit will receive currents or voltages having different magnitudes, so that different currents or voltage may be measured on the sensing terminal of the receiving circuit.

12 FIG. 11 11 FIGS.A-D 12 FIG. 1 3 1 3 1100 1 3 1100 illustrates the correspondence of the equivalent capacitance and the sensing signal VRX. As mentioned above, the sensing signal VRX on the vertical axis may be a signal in the voltage form or current form. The equivalent capacitance on the horizontal axis corresponds to the number of common electrodes electrically connected to the sensing electrode RX. As shown in, each of the common electrodes COM-COMhas a coupling capacitance with the corresponding touch sensor on the panel. When the sensing electrode RX is electrically connected to any of the common electrodes COM-COM, the equivalent capacitance detected by the sensing circuitthrough the sensing electrode RX is equivalent to the combination of the coupling capacitance of the sensing electrode RX itself and the coupling capacitance corresponding to the connected common electrode(s). In other words, when the sensing electrode RX is electrically connected to more common electrodes, the equivalent capacitance value corresponding to the sensing electrode RX is larger, and the generated sensing signal VRX is also larger. Their correspondence is shown in. Preferably, through well design of the sizes of the sensing electrode RX and the common electrodes COM-COMon the knob, the equivalent capacitance may fall in the linear region, so that the sensing signal VRX detected by the sensing circuitmay effectively reflect the variation of the equivalent capacitance.

13 FIG. 13 FIG. 1 2 1 2 1 2 1 1 2 1 2 illustrates the rotation operation of the knob corresponding to different states. In the absence of pressing, the knob may have 3 states: 0C, 1C and 2C, according to the number of common electrodes electrically connected to the sensing electrode RX. As shown in, under the state 0C, the connecting post of the electrode ring of the sensing electrode RX overlaps the sawtooth recessing parts on the electrode rings of the common electrodes COMand COM, so that neither the common electrode COMnor the common electrode COMis electrically connected to the sensing electrode RX. Under the state 1C, the connecting post of the electrode ring of the sensing electrode RX overlaps the sawtooth protruding part on the electrode ring of the common electrode COMand the sawtooth recessing part on the electrode ring of the common electrode COM, so that only the common electrode COMis electrically connected to the sensing electrode RX. Under the state 2C, the connecting post of the electrode ring of the sensing electrode RX overlaps the sawtooth protruding part on the electrode rings of the common electrodes COMand COM, so that the common electrodes COMand COMare both electrically connected to the sensing electrode RX.

13 FIG. 1 2 3 The transition between each state is also shown in. In this embodiment, the electrode rings of the common electrodes COMand COMrotate with the knob, while the electrode rings of the common electrode COMand the sensing electrode RX are fixed. The knob may rotate clockwise or counterclockwise. In the clockwise rotation, the state of the knob changes in the order of 0C, 2C, 1C, 0C, 2C, 1C. etc., and in the counterclockwise rotation, the state of the knob changes in the order of 1C, 2C, 0C, 1C, 2C, 0C. etc. The sensing circuit of the knob may thereby determine its rotation direction and calculate the rotation angle based on the variation and sequence of the knob's state within a period of time.

1 2 As can be seen, through the sawtooth structure of the common electrode ring, the protruding or recessing part of the sawtooth may be adjusted to be aligned with the connecting post on the sensing electrode ring when the knob rotates, so as to change the number of common electrodes electrically connected to the sensing electrode RX at any time. Therefore, the sawtooth structure of the common electrode ring should be well designed, in order to realize the variations of different states 0C-2C during the rotation process. In this embodiment, it may be designed that the sawtooth width on the electrode ring of the common electrode COMis larger, while the sawtooth width on the electrode ring of the common electrode COMis smaller, and each sawtooth on the two electrode rings corresponds to each other and rotates synchronously, so that the state of the knob meets a predetermined change pattern in clockwise or counterclockwise rotation. Note that the above method of using a sawtooth structural design to change electrode coupling during the knob rotation is one of various implementations of the present invention. In other embodiments, as long as the number of common electrodes on the knob electrically connected to the sensing electrode RX may change with the operation of the knob, and the change method may be used to determine the rotation direction and/or angle of the knob, the related knob structure and determination method should belong to the scope of the present invention.

14 FIG. 14 FIG. 900 1 3 illustrates the pressing operation of the knob corresponding to different states. As mentioned above, in the absence of pressing, the knob may be in one of the three states 0C-2C, where the state 0C is taken as an example in. When the knob is pressed, the pressing clipis pressed down, so that the common electrodes COM-COMare all electrically connected to the sensing electrode RX. At this time, the knob is in the state 3C. The sensing circuit of the knob may thereby determine whether the knob is pressed according to the state of the knob.

As mentioned above, different states 0C-3C of the knob correspond to the number of common electrodes electrically connected to the sensing electrode RX, which further corresponds to the signal amount on the touch sensor under the sensing electrode RX. The sensing circuit of the knob may determine which state the knob is in according to the magnitude of the signal amount. In an embodiment, the state of the knob may affect the signal distribution of multiple touch sensors near the sensing electrode RX. In order to achieve more accurate determination of the knob state, the algorithm in the processing circuit may refer to the signal distribution of these touch sensors and use appropriate threshold values to determine the state of the knob.

15 FIG. 12 FIG. 1 3 1 1 2 2 3 3 For example, as shown in, in the correspondence of the equivalent capacitance and the sensing signal VRX shown in, the states 0C-3C respectively correspond to different equivalent capacitances and different magnitudes of the sensing signal VRX. In this embodiment, the processing circuit may compare the signal amount of the sensing signal VRX with any threshold value TH-TH, to determine which state the knob is in. In detail, when determining that the signal amount of the sensing signal VRX is smaller than the threshold value TH, the processing circuit may determine that the knob is in the state 0C. When determining that the signal amount of the sensing signal VRX is greater than the threshold value THbut smaller than the threshold value TH, the processing circuit may determine that the knob is in the state 1C. When determining that the signal amount of the sensing signal VRX is greater than the threshold value THbut smaller than the threshold value TH, the processing circuit may determine that the knob is in the state 2C. When determining that the signal amount of the sensing signal VRX is greater than the threshold value TH, the processing circuit may determine that the knob is in the state 3C.

16 FIG. 16 FIG. 1 3 is a schematic diagram of the signal distribution on the touch sensor corresponding to the sensing electrode RX according to an embodiment of the present invention, where exemplary distributions of signal amount (i.e., signal variation) under the states 0C-3C are shown, where each grid may represent a touch sensor. In detail, the touch sensor located in the middle under the sensing electrode RX has the largest signal amount, of which the values are 0, 50, 100 and 150 in the states 0C-3C, respectively. Therefore, in an embodiment, the threshold values TH-THused to determine the knob state may be set to 25, 75 and 125, respectively, to distinguish the knob operations in different states. In another embodiment, the signal amounts of multiple touch sensors (such as the 9 touch sensors shown in) that may be affected by the sensing electrode RX are also combined to serve as the sensing signal VRX received by the sensing circuit, with appropriate threshold value settings to realize the determination of the knob operation. Alternatively, the sensing electrode RX may be disposed above multiple touch sensors; that is, the area of the sensing electrode RX covers multiple touch Sensors. Therefore, the sensing circuit may obtain the sensing signals VRX of these touch sensors to increase the signal amount and enhance the performance of knob determination.

3 FIG. 7 FIG. 3 Note that the present invention aims at providing a knob on a touch panel and a related sensing circuit, where only one sensing electrode needs to be provided on the knob, which may simplify the detection method of the sensing circuit and save the cost of the sensing circuit. Those skilled in the art may make modifications and alterations accordingly. For example, the knob structure shown inoris one of various embodiments of the present invention. In another embodiment, the electrode ring in the knob may be disposed in another method. For example, the electrode ring of the common electrode COMfor pressing detection may be disposed in the inner side. Alternatively, in other embodiments, there may be more than 4 electrode rings included in the knob, and the number of disposed electrode rings is not limited to those described in the present disclosure.

In addition, in the above embodiments, the electrode ring of each electrode is arranged in the horizontal direction along the knob shell, so as to rotate with the rotation of the knob. The structure of the present invention is not limited thereto. In another embodiment, the positions of the electrode rings may also be changed. For example, parts or all of the electrode rings may be designed as an electrode piece vertical to the bottom of the knob. As long as the electrode ring can move or rotate with the rotation of the knob, and thereby change the electrical connection between the sensing electrode and the common electrode under different knob states, the related implementations should fall within the scope of the present invention.

1 2 1 2 70 1 2 3 7 FIG. Moreover, in the embodiments of the present invention, the sizes of the sensing electrodes may be designed according to system requirements. For example, if two common electrodes COMand COMare applied, the common electrodes COMand COMmay be designed to have different sizes to enhance the separation between different states. In a preferable embodiment, in the structure of the knobshown in, the areas of the common electrodes COM, COMand COMmay be designed to have the ratio 1:2:3, to achieve the optimal knob determination effect.

In addition, in some embodiments, the knob may be disposed on the touch panel, and the sensing circuit of the knob may have both knob detection and touch sensing functions. In other embodiments, the knob may be disposed on a general display panel without the touch function, or on the casing of a general tablet or an electronic device, but not limited thereto. The sensing electrode and common electrode of the knob may also be disposed in any appropriate manner. For example, a sensing electrode piece and a common electrode piece may be attached to a predetermined position on the panel, and the corresponding electrode posts and electrode rings are connected above, and then the shell of the knob is covered on each electrode element. Alternatively, a sensing electrode piece and a common electrode piece may also be attached to the base of the knob, then connected to the electrode post and electrode ring, covered by the shell, and then the entire knob is fitted to the desired position.

Note that in the above embodiment, the sensing circuit may apply a reference voltage to the touch sensor corresponding to the common electrodes; hence, the sensing signals on the sensing electrode may be the signal variations generated by the reference voltage from the common electrode. In another embodiment, the signal variations of the sensing signal may also be generated based on the reference voltage (e.g., the ground voltage) provided by a touch object (such as a finger of the user) operating the knob. In such a situation, the knob may be disposed with a conductor inside, and the conductor may be coupled to the corresponding common electrode inside the knob. Therefore, during the knob operation (e.g., the user turns the knob with fingers), the reference voltage from the touch object may be sent to the common electrode through the conductor, to provide a signal for the sensing electrode when the common electrode is electrically connected to the sensing electrode, so as to generate signal amounts on the touch sensor corresponding to the sensing electrode. In this way, the touch sensor corresponding to the common electrode does not need to further receive a reference voltage, and the reference voltage is provided by the touch object instead. In another embodiment, a reference voltage may be applied to the touch sensor corresponding to the common electrode, and combined with the voltage signal of the conductor to obtain a larger signal amount, thereby improving the performance of knob detection.

17 FIG. 170 1700 1702 1704 1700 170 170 1700 The conductor may be implemented in any appropriate manner. In an embodiment, the conductor may be a conductive ring disposed on the surface of the knob, and the conductive ring may be contacted by the touch object when the touch object is operating the knob. Alternatively, the conductor may be or include a metal layer contained inside the conductor. As shown in, the knobis disposed to have a metal layerand a rubber layer, and the shellof the knob may be used to cover and protect the internal electrodes. The metal layeris a sheet conductor covering the entire bottom of the knoband exposed around the knob. This is an easily accessible position when the touch object operates the knob, so the ground voltage from the touch object may be forwarded to the corresponding common electrode. In this embodiment, more signal amounts may be provided for the sensing electrode through the huge parasitic capacitance generated by the large-area sheet conductor of the metal layer.

To sum up, the present invention provides the structure of a knob on a touch panel and a sensing circuit for controlling the knob and a related operation method. Only one sensing electrode needs to be disposed in the knob, and operated with multiple common electrodes to realize various operations of the knob. The sensing circuit only needs to detect and receive the sensing signal through the only one sensing electrode. According to the operations of the knob such as rotation or pressing, the sensing electrode may be electrically connected to different numbers of common electrodes in different states, so as to generate different signal amounts on the touch sensor corresponding to the sensing electrode. Therefore, the sensing circuit may determine various operations of the knob according to the detected signal amount.

Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.